w1.c revision 12003375acd879e498c6c511faf27531296f9640
1/* 2 * w1.c 3 * 4 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru> 5 * 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 */ 21 22#include <linux/delay.h> 23#include <linux/kernel.h> 24#include <linux/module.h> 25#include <linux/moduleparam.h> 26#include <linux/list.h> 27#include <linux/interrupt.h> 28#include <linux/spinlock.h> 29#include <linux/timer.h> 30#include <linux/device.h> 31#include <linux/slab.h> 32#include <linux/sched.h> 33#include <linux/kthread.h> 34 35#include <asm/atomic.h> 36 37#include "w1.h" 38#include "w1_log.h" 39#include "w1_int.h" 40#include "w1_family.h" 41#include "w1_netlink.h" 42 43MODULE_LICENSE("GPL"); 44MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>"); 45MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol."); 46 47static int w1_timeout = 10; 48static int w1_control_timeout = 1; 49int w1_max_slave_count = 10; 50int w1_max_slave_ttl = 10; 51 52module_param_named(timeout, w1_timeout, int, 0); 53module_param_named(control_timeout, w1_control_timeout, int, 0); 54module_param_named(max_slave_count, w1_max_slave_count, int, 0); 55module_param_named(slave_ttl, w1_max_slave_ttl, int, 0); 56 57DECLARE_MUTEX(w1_mlock); 58LIST_HEAD(w1_masters); 59 60static struct task_struct *w1_control_thread; 61 62static int w1_master_match(struct device *dev, struct device_driver *drv) 63{ 64 return 1; 65} 66 67static int w1_master_probe(struct device *dev) 68{ 69 return -ENODEV; 70} 71 72static void w1_master_release(struct device *dev) 73{ 74 struct w1_master *md = dev_to_w1_master(dev); 75 76 dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name); 77 memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); 78 kfree(md); 79} 80 81static void w1_slave_release(struct device *dev) 82{ 83 struct w1_slave *sl = dev_to_w1_slave(dev); 84 85 printk("%s: Releasing %s.\n", __func__, sl->name); 86 87 while (atomic_read(&sl->refcnt)) { 88 printk("Waiting for %s to become free: refcnt=%d.\n", 89 sl->name, atomic_read(&sl->refcnt)); 90 if (msleep_interruptible(1000)) 91 flush_signals(current); 92 } 93 94 w1_family_put(sl->family); 95 sl->master->slave_count--; 96 97 complete(&sl->released); 98} 99 100static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf) 101{ 102 struct w1_slave *sl = dev_to_w1_slave(dev); 103 104 return sprintf(buf, "%s\n", sl->name); 105} 106 107static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count) 108{ 109 struct w1_slave *sl = kobj_to_w1_slave(kobj); 110 111 if (off > 8) { 112 count = 0; 113 } else { 114 if (off + count > 8) 115 count = 8 - off; 116 117 memcpy(buf, (u8 *)&sl->reg_num, count); 118 } 119 120 return count; 121} 122 123static struct device_attribute w1_slave_attr_name = 124 __ATTR(name, S_IRUGO, w1_slave_read_name, NULL); 125 126static struct bin_attribute w1_slave_attr_bin_id = { 127 .attr = { 128 .name = "id", 129 .mode = S_IRUGO, 130 .owner = THIS_MODULE, 131 }, 132 .size = 8, 133 .read = w1_slave_read_id, 134}; 135 136/* Default family */ 137 138static ssize_t w1_default_write(struct kobject *kobj, char *buf, loff_t off, size_t count) 139{ 140 struct w1_slave *sl = kobj_to_w1_slave(kobj); 141 142 if (down_interruptible(&sl->master->mutex)) { 143 count = 0; 144 goto out; 145 } 146 147 if (w1_reset_select_slave(sl)) { 148 count = 0; 149 goto out_up; 150 } 151 152 w1_write_block(sl->master, buf, count); 153 154out_up: 155 up(&sl->master->mutex); 156out: 157 return count; 158} 159 160static ssize_t w1_default_read(struct kobject *kobj, char *buf, loff_t off, size_t count) 161{ 162 struct w1_slave *sl = kobj_to_w1_slave(kobj); 163 164 if (down_interruptible(&sl->master->mutex)) { 165 count = 0; 166 goto out; 167 } 168 169 w1_read_block(sl->master, buf, count); 170 171 up(&sl->master->mutex); 172out: 173 return count; 174} 175 176static struct bin_attribute w1_default_attr = { 177 .attr = { 178 .name = "rw", 179 .mode = S_IRUGO | S_IWUSR, 180 .owner = THIS_MODULE, 181 }, 182 .size = PAGE_SIZE, 183 .read = w1_default_read, 184 .write = w1_default_write, 185}; 186 187static int w1_default_add_slave(struct w1_slave *sl) 188{ 189 return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr); 190} 191 192static void w1_default_remove_slave(struct w1_slave *sl) 193{ 194 sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr); 195} 196 197static struct w1_family_ops w1_default_fops = { 198 .add_slave = w1_default_add_slave, 199 .remove_slave = w1_default_remove_slave, 200}; 201 202static struct w1_family w1_default_family = { 203 .fops = &w1_default_fops, 204}; 205 206static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size); 207 208static struct bus_type w1_bus_type = { 209 .name = "w1", 210 .match = w1_master_match, 211 .uevent = w1_uevent, 212}; 213 214struct device_driver w1_master_driver = { 215 .name = "w1_master_driver", 216 .bus = &w1_bus_type, 217 .probe = w1_master_probe, 218}; 219 220struct device w1_master_device = { 221 .parent = NULL, 222 .bus = &w1_bus_type, 223 .bus_id = "w1 bus master", 224 .driver = &w1_master_driver, 225 .release = &w1_master_release 226}; 227 228struct device_driver w1_slave_driver = { 229 .name = "w1_slave_driver", 230 .bus = &w1_bus_type, 231}; 232 233struct device w1_slave_device = { 234 .parent = NULL, 235 .bus = &w1_bus_type, 236 .bus_id = "w1 bus slave", 237 .driver = &w1_slave_driver, 238 .release = &w1_slave_release 239}; 240 241static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf) 242{ 243 struct w1_master *md = dev_to_w1_master(dev); 244 ssize_t count; 245 246 if (down_interruptible (&md->mutex)) 247 return -EBUSY; 248 249 count = sprintf(buf, "%s\n", md->name); 250 251 up(&md->mutex); 252 253 return count; 254} 255 256static ssize_t w1_master_attribute_store_search(struct device * dev, 257 struct device_attribute *attr, 258 const char * buf, size_t count) 259{ 260 struct w1_master *md = dev_to_w1_master(dev); 261 262 if (down_interruptible (&md->mutex)) 263 return -EBUSY; 264 265 md->search_count = simple_strtol(buf, NULL, 0); 266 267 up(&md->mutex); 268 269 return count; 270} 271 272static ssize_t w1_master_attribute_show_search(struct device *dev, 273 struct device_attribute *attr, 274 char *buf) 275{ 276 struct w1_master *md = dev_to_w1_master(dev); 277 ssize_t count; 278 279 if (down_interruptible (&md->mutex)) 280 return -EBUSY; 281 282 count = sprintf(buf, "%d\n", md->search_count); 283 284 up(&md->mutex); 285 286 return count; 287} 288 289static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf) 290{ 291 struct w1_master *md = dev_to_w1_master(dev); 292 ssize_t count; 293 294 if (down_interruptible(&md->mutex)) 295 return -EBUSY; 296 297 count = sprintf(buf, "0x%p\n", md->bus_master); 298 299 up(&md->mutex); 300 return count; 301} 302 303static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf) 304{ 305 ssize_t count; 306 count = sprintf(buf, "%d\n", w1_timeout); 307 return count; 308} 309 310static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf) 311{ 312 struct w1_master *md = dev_to_w1_master(dev); 313 ssize_t count; 314 315 if (down_interruptible(&md->mutex)) 316 return -EBUSY; 317 318 count = sprintf(buf, "%d\n", md->max_slave_count); 319 320 up(&md->mutex); 321 return count; 322} 323 324static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf) 325{ 326 struct w1_master *md = dev_to_w1_master(dev); 327 ssize_t count; 328 329 if (down_interruptible(&md->mutex)) 330 return -EBUSY; 331 332 count = sprintf(buf, "%lu\n", md->attempts); 333 334 up(&md->mutex); 335 return count; 336} 337 338static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf) 339{ 340 struct w1_master *md = dev_to_w1_master(dev); 341 ssize_t count; 342 343 if (down_interruptible(&md->mutex)) 344 return -EBUSY; 345 346 count = sprintf(buf, "%d\n", md->slave_count); 347 348 up(&md->mutex); 349 return count; 350} 351 352static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf) 353{ 354 struct w1_master *md = dev_to_w1_master(dev); 355 int c = PAGE_SIZE; 356 357 if (down_interruptible(&md->mutex)) 358 return -EBUSY; 359 360 if (md->slave_count == 0) 361 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n"); 362 else { 363 struct list_head *ent, *n; 364 struct w1_slave *sl; 365 366 list_for_each_safe(ent, n, &md->slist) { 367 sl = list_entry(ent, struct w1_slave, w1_slave_entry); 368 369 c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name); 370 } 371 } 372 373 up(&md->mutex); 374 375 return PAGE_SIZE - c; 376} 377 378#define W1_MASTER_ATTR_RO(_name, _mode) \ 379 struct device_attribute w1_master_attribute_##_name = \ 380 __ATTR(w1_master_##_name, _mode, \ 381 w1_master_attribute_show_##_name, NULL) 382 383#define W1_MASTER_ATTR_RW(_name, _mode) \ 384 struct device_attribute w1_master_attribute_##_name = \ 385 __ATTR(w1_master_##_name, _mode, \ 386 w1_master_attribute_show_##_name, \ 387 w1_master_attribute_store_##_name) 388 389static W1_MASTER_ATTR_RO(name, S_IRUGO); 390static W1_MASTER_ATTR_RO(slaves, S_IRUGO); 391static W1_MASTER_ATTR_RO(slave_count, S_IRUGO); 392static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO); 393static W1_MASTER_ATTR_RO(attempts, S_IRUGO); 394static W1_MASTER_ATTR_RO(timeout, S_IRUGO); 395static W1_MASTER_ATTR_RO(pointer, S_IRUGO); 396static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO); 397 398static struct attribute *w1_master_default_attrs[] = { 399 &w1_master_attribute_name.attr, 400 &w1_master_attribute_slaves.attr, 401 &w1_master_attribute_slave_count.attr, 402 &w1_master_attribute_max_slave_count.attr, 403 &w1_master_attribute_attempts.attr, 404 &w1_master_attribute_timeout.attr, 405 &w1_master_attribute_pointer.attr, 406 &w1_master_attribute_search.attr, 407 NULL 408}; 409 410static struct attribute_group w1_master_defattr_group = { 411 .attrs = w1_master_default_attrs, 412}; 413 414int w1_create_master_attributes(struct w1_master *master) 415{ 416 return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group); 417} 418 419void w1_destroy_master_attributes(struct w1_master *master) 420{ 421 sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group); 422} 423 424#ifdef CONFIG_HOTPLUG 425static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size) 426{ 427 struct w1_master *md = NULL; 428 struct w1_slave *sl = NULL; 429 char *event_owner, *name; 430 int err, cur_index=0, cur_len=0; 431 432 if (dev->driver == &w1_master_driver) { 433 md = container_of(dev, struct w1_master, dev); 434 event_owner = "master"; 435 name = md->name; 436 } else if (dev->driver == &w1_slave_driver) { 437 sl = container_of(dev, struct w1_slave, dev); 438 event_owner = "slave"; 439 name = sl->name; 440 } else { 441 dev_dbg(dev, "Unknown event.\n"); 442 return -EINVAL; 443 } 444 445 dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", event_owner, name, dev->bus_id); 446 447 if (dev->driver != &w1_slave_driver || !sl) 448 return 0; 449 450 err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_FID=%02X", sl->reg_num.family); 451 if (err) 452 return err; 453 454 err = add_uevent_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_SLAVE_ID=%024LX", (u64)sl->reg_num.id); 455 if (err) 456 return err; 457 458 return 0; 459}; 460#else 461static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size) 462{ 463 return 0; 464} 465#endif 466 467static int __w1_attach_slave_device(struct w1_slave *sl) 468{ 469 int err; 470 471 sl->dev.parent = &sl->master->dev; 472 sl->dev.driver = &w1_slave_driver; 473 sl->dev.bus = &w1_bus_type; 474 sl->dev.release = &w1_slave_release; 475 476 snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id), 477 "%02x-%012llx", 478 (unsigned int) sl->reg_num.family, 479 (unsigned long long) sl->reg_num.id); 480 snprintf(&sl->name[0], sizeof(sl->name), 481 "%02x-%012llx", 482 (unsigned int) sl->reg_num.family, 483 (unsigned long long) sl->reg_num.id); 484 485 dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, &sl->dev.bus_id[0]); 486 487 err = device_register(&sl->dev); 488 if (err < 0) { 489 dev_err(&sl->dev, 490 "Device registration [%s] failed. err=%d\n", 491 sl->dev.bus_id, err); 492 return err; 493 } 494 495 /* Create "name" entry */ 496 err = device_create_file(&sl->dev, &w1_slave_attr_name); 497 if (err < 0) { 498 dev_err(&sl->dev, 499 "sysfs file creation for [%s] failed. err=%d\n", 500 sl->dev.bus_id, err); 501 goto out_unreg; 502 } 503 504 /* Create "id" entry */ 505 err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id); 506 if (err < 0) { 507 dev_err(&sl->dev, 508 "sysfs file creation for [%s] failed. err=%d\n", 509 sl->dev.bus_id, err); 510 goto out_rem1; 511 } 512 513 /* if the family driver needs to initialize something... */ 514 if (sl->family->fops && sl->family->fops->add_slave && 515 ((err = sl->family->fops->add_slave(sl)) < 0)) { 516 dev_err(&sl->dev, 517 "sysfs file creation for [%s] failed. err=%d\n", 518 sl->dev.bus_id, err); 519 goto out_rem2; 520 } 521 522 list_add_tail(&sl->w1_slave_entry, &sl->master->slist); 523 524 return 0; 525 526out_rem2: 527 sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id); 528out_rem1: 529 device_remove_file(&sl->dev, &w1_slave_attr_name); 530out_unreg: 531 device_unregister(&sl->dev); 532 return err; 533} 534 535static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn) 536{ 537 struct w1_slave *sl; 538 struct w1_family *f; 539 int err; 540 struct w1_netlink_msg msg; 541 542 sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL); 543 if (!sl) { 544 dev_err(&dev->dev, 545 "%s: failed to allocate new slave device.\n", 546 __func__); 547 return -ENOMEM; 548 } 549 550 memset(sl, 0, sizeof(*sl)); 551 552 sl->owner = THIS_MODULE; 553 sl->master = dev; 554 set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); 555 556 memset(&msg, 0, sizeof(msg)); 557 memcpy(&sl->reg_num, rn, sizeof(sl->reg_num)); 558 atomic_set(&sl->refcnt, 0); 559 init_completion(&sl->released); 560 561 spin_lock(&w1_flock); 562 f = w1_family_registered(rn->family); 563 if (!f) { 564 f= &w1_default_family; 565 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n", 566 rn->family, rn->family, 567 (unsigned long long)rn->id, rn->crc); 568 } 569 __w1_family_get(f); 570 spin_unlock(&w1_flock); 571 572 sl->family = f; 573 574 575 err = __w1_attach_slave_device(sl); 576 if (err < 0) { 577 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__, 578 sl->name); 579 w1_family_put(sl->family); 580 kfree(sl); 581 return err; 582 } 583 584 sl->ttl = dev->slave_ttl; 585 dev->slave_count++; 586 587 memcpy(msg.id.id, rn, sizeof(msg.id)); 588 msg.type = W1_SLAVE_ADD; 589 w1_netlink_send(dev, &msg); 590 591 return 0; 592} 593 594static void w1_slave_detach(struct w1_slave *sl) 595{ 596 struct w1_netlink_msg msg; 597 598 dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl); 599 600 list_del(&sl->w1_slave_entry); 601 602 if (sl->family->fops && sl->family->fops->remove_slave) 603 sl->family->fops->remove_slave(sl); 604 605 memset(&msg, 0, sizeof(msg)); 606 memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id)); 607 msg.type = W1_SLAVE_REMOVE; 608 w1_netlink_send(sl->master, &msg); 609 610 sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id); 611 device_remove_file(&sl->dev, &w1_slave_attr_name); 612 device_unregister(&sl->dev); 613 614 wait_for_completion(&sl->released); 615 kfree(sl); 616} 617 618static struct w1_master *w1_search_master(void *data) 619{ 620 struct w1_master *dev; 621 int found = 0; 622 623 down(&w1_mlock); 624 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 625 if (dev->bus_master->data == data) { 626 found = 1; 627 atomic_inc(&dev->refcnt); 628 break; 629 } 630 } 631 up(&w1_mlock); 632 633 return (found)?dev:NULL; 634} 635 636struct w1_master *w1_search_master_id(u32 id) 637{ 638 struct w1_master *dev; 639 int found = 0; 640 641 down(&w1_mlock); 642 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 643 if (dev->id == id) { 644 found = 1; 645 atomic_inc(&dev->refcnt); 646 break; 647 } 648 } 649 up(&w1_mlock); 650 651 return (found)?dev:NULL; 652} 653 654struct w1_slave *w1_search_slave(struct w1_reg_num *id) 655{ 656 struct w1_master *dev; 657 struct w1_slave *sl = NULL; 658 int found = 0; 659 660 down(&w1_mlock); 661 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 662 down(&dev->mutex); 663 list_for_each_entry(sl, &dev->slist, w1_slave_entry) { 664 if (sl->reg_num.family == id->family && 665 sl->reg_num.id == id->id && 666 sl->reg_num.crc == id->crc) { 667 found = 1; 668 atomic_inc(&dev->refcnt); 669 atomic_inc(&sl->refcnt); 670 break; 671 } 672 } 673 up(&dev->mutex); 674 675 if (found) 676 break; 677 } 678 up(&w1_mlock); 679 680 return (found)?sl:NULL; 681} 682 683void w1_reconnect_slaves(struct w1_family *f) 684{ 685 struct w1_master *dev; 686 687 down(&w1_mlock); 688 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 689 dev_dbg(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n", 690 dev->name, f->fid); 691 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags); 692 } 693 up(&w1_mlock); 694} 695 696static void w1_slave_found(void *data, u64 rn) 697{ 698 int slave_count; 699 struct w1_slave *sl; 700 struct list_head *ent; 701 struct w1_reg_num *tmp; 702 int family_found = 0; 703 struct w1_master *dev; 704 u64 rn_le = cpu_to_le64(rn); 705 706 dev = w1_search_master(data); 707 if (!dev) { 708 printk(KERN_ERR "Failed to find w1 master device for data %p, " 709 "it is impossible.\n", data); 710 return; 711 } 712 713 tmp = (struct w1_reg_num *) &rn; 714 715 slave_count = 0; 716 list_for_each(ent, &dev->slist) { 717 718 sl = list_entry(ent, struct w1_slave, w1_slave_entry); 719 720 if (sl->reg_num.family == tmp->family && 721 sl->reg_num.id == tmp->id && 722 sl->reg_num.crc == tmp->crc) { 723 set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); 724 break; 725 } else if (sl->reg_num.family == tmp->family) { 726 family_found = 1; 727 break; 728 } 729 730 slave_count++; 731 } 732 733 if (slave_count == dev->slave_count && 734 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) { 735 w1_attach_slave_device(dev, tmp); 736 } 737 738 atomic_dec(&dev->refcnt); 739} 740 741/** 742 * Performs a ROM Search & registers any devices found. 743 * The 1-wire search is a simple binary tree search. 744 * For each bit of the address, we read two bits and write one bit. 745 * The bit written will put to sleep all devies that don't match that bit. 746 * When the two reads differ, the direction choice is obvious. 747 * When both bits are 0, we must choose a path to take. 748 * When we can scan all 64 bits without having to choose a path, we are done. 749 * 750 * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com 751 * 752 * @dev The master device to search 753 * @cb Function to call when a device is found 754 */ 755void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb) 756{ 757 u64 last_rn, rn, tmp64; 758 int i, slave_count = 0; 759 int last_zero, last_device; 760 int search_bit, desc_bit; 761 u8 triplet_ret = 0; 762 763 search_bit = 0; 764 rn = last_rn = 0; 765 last_device = 0; 766 last_zero = -1; 767 768 desc_bit = 64; 769 770 while ( !last_device && (slave_count++ < dev->max_slave_count) ) { 771 last_rn = rn; 772 rn = 0; 773 774 /* 775 * Reset bus and all 1-wire device state machines 776 * so they can respond to our requests. 777 * 778 * Return 0 - device(s) present, 1 - no devices present. 779 */ 780 if (w1_reset_bus(dev)) { 781 dev_dbg(&dev->dev, "No devices present on the wire.\n"); 782 break; 783 } 784 785 /* Start the search */ 786 w1_write_8(dev, search_type); 787 for (i = 0; i < 64; ++i) { 788 /* Determine the direction/search bit */ 789 if (i == desc_bit) 790 search_bit = 1; /* took the 0 path last time, so take the 1 path */ 791 else if (i > desc_bit) 792 search_bit = 0; /* take the 0 path on the next branch */ 793 else 794 search_bit = ((last_rn >> i) & 0x1); 795 796 /** Read two bits and write one bit */ 797 triplet_ret = w1_triplet(dev, search_bit); 798 799 /* quit if no device responded */ 800 if ( (triplet_ret & 0x03) == 0x03 ) 801 break; 802 803 /* If both directions were valid, and we took the 0 path... */ 804 if (triplet_ret == 0) 805 last_zero = i; 806 807 /* extract the direction taken & update the device number */ 808 tmp64 = (triplet_ret >> 2); 809 rn |= (tmp64 << i); 810 } 811 812 if ( (triplet_ret & 0x03) != 0x03 ) { 813 if ( (desc_bit == last_zero) || (last_zero < 0)) 814 last_device = 1; 815 desc_bit = last_zero; 816 cb(dev->bus_master->data, rn); 817 } 818 } 819} 820 821static int w1_control(void *data) 822{ 823 struct w1_slave *sl, *sln; 824 struct w1_master *dev, *n; 825 int have_to_wait = 0; 826 827 while (!kthread_should_stop() || have_to_wait) { 828 have_to_wait = 0; 829 830 try_to_freeze(); 831 msleep_interruptible(w1_control_timeout * 1000); 832 833 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) { 834 if (!kthread_should_stop() && !dev->flags) 835 continue; 836 /* 837 * Little race: we can create thread but not set the flag. 838 * Get a chance for external process to set flag up. 839 */ 840 if (!dev->initialized) { 841 have_to_wait = 1; 842 continue; 843 } 844 845 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) { 846 set_bit(W1_MASTER_NEED_EXIT, &dev->flags); 847 848 down(&w1_mlock); 849 list_del(&dev->w1_master_entry); 850 up(&w1_mlock); 851 852 down(&dev->mutex); 853 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 854 w1_slave_detach(sl); 855 } 856 w1_destroy_master_attributes(dev); 857 up(&dev->mutex); 858 atomic_dec(&dev->refcnt); 859 continue; 860 } 861 862 if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) { 863 dev_dbg(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name); 864 down(&dev->mutex); 865 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 866 if (sl->family->fid == W1_FAMILY_DEFAULT) { 867 struct w1_reg_num rn; 868 869 memcpy(&rn, &sl->reg_num, sizeof(rn)); 870 w1_slave_detach(sl); 871 872 w1_attach_slave_device(dev, &rn); 873 } 874 } 875 dev_dbg(&dev->dev, "Reconnecting slaves in device %s has been finished.\n", dev->name); 876 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags); 877 up(&dev->mutex); 878 } 879 } 880 } 881 882 return 0; 883} 884 885void w1_search_process(struct w1_master *dev, u8 search_type) 886{ 887 struct w1_slave *sl, *sln; 888 889 list_for_each_entry(sl, &dev->slist, w1_slave_entry) 890 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags); 891 892 w1_search_devices(dev, search_type, w1_slave_found); 893 894 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 895 if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) { 896 w1_slave_detach(sl); 897 898 dev->slave_count--; 899 } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags)) 900 sl->ttl = dev->slave_ttl; 901 } 902 903 if (dev->search_count > 0) 904 dev->search_count--; 905} 906 907int w1_process(void *data) 908{ 909 struct w1_master *dev = (struct w1_master *) data; 910 911 while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) { 912 try_to_freeze(); 913 msleep_interruptible(w1_timeout * 1000); 914 915 if (kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) 916 break; 917 918 if (!dev->initialized) 919 continue; 920 921 if (dev->search_count == 0) 922 continue; 923 924 if (down_interruptible(&dev->mutex)) 925 continue; 926 927 w1_search_process(dev, W1_SEARCH); 928 929 up(&dev->mutex); 930 } 931 932 atomic_dec(&dev->refcnt); 933 934 return 0; 935} 936 937static int w1_init(void) 938{ 939 int retval; 940 941 printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n"); 942 943 w1_init_netlink(); 944 945 retval = bus_register(&w1_bus_type); 946 if (retval) { 947 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval); 948 goto err_out_exit_init; 949 } 950 951 retval = driver_register(&w1_master_driver); 952 if (retval) { 953 printk(KERN_ERR 954 "Failed to register master driver. err=%d.\n", 955 retval); 956 goto err_out_bus_unregister; 957 } 958 959 retval = driver_register(&w1_slave_driver); 960 if (retval) { 961 printk(KERN_ERR 962 "Failed to register master driver. err=%d.\n", 963 retval); 964 goto err_out_master_unregister; 965 } 966 967 w1_control_thread = kthread_run(w1_control, NULL, "w1_control"); 968 if (IS_ERR(w1_control_thread)) { 969 retval = PTR_ERR(w1_control_thread); 970 printk(KERN_ERR "Failed to create control thread. err=%d\n", 971 retval); 972 goto err_out_slave_unregister; 973 } 974 975 return 0; 976 977err_out_slave_unregister: 978 driver_unregister(&w1_slave_driver); 979 980err_out_master_unregister: 981 driver_unregister(&w1_master_driver); 982 983err_out_bus_unregister: 984 bus_unregister(&w1_bus_type); 985 986err_out_exit_init: 987 return retval; 988} 989 990static void w1_fini(void) 991{ 992 struct w1_master *dev; 993 994 list_for_each_entry(dev, &w1_masters, w1_master_entry) 995 __w1_remove_master_device(dev); 996 997 w1_fini_netlink(); 998 999 kthread_stop(w1_control_thread); 1000 1001 driver_unregister(&w1_slave_driver); 1002 driver_unregister(&w1_master_driver); 1003 bus_unregister(&w1_bus_type); 1004} 1005 1006module_init(w1_init); 1007module_exit(w1_fini); 1008